EP0563992B1 - Method and apparatus for the manufacture of metallic surface layers on substrates - Google Patents

Abstract

A novel method for manufacturing substrates with defined metallic surface structure is specified, which method can be used advantageously in particular in the manufacture of reflection holograms on banknotes. In this case the metallic surface elements are produced on a master, for example a printing roller, in peelable form and then transferred directly from the master onto the respective substrate. <IMAGE>

Description

The invention relates to a method and a device for the production of locally limited metal layers Substrates with a possibly rough surface in the transfer process, where the metal layers on one Prepared transfer area and then on the substrate be transmitted.

Metallic surface elements come in the area of anti-counterfeiting of value documents a substantial Meaning too. On the one hand, metallic surfaces offer good reflection protection due to its reflective properties, because the reflective surfaces with copy technology Means cannot be adjusted. in the The simplest case is usually metal printing inks used to make shiny metallic surface or printed images to create. Because of the grainy fine structure these methods can only be used for metallic surfaces, where only minimal requirements are placed on the Reflection behavior of the surface and where no defined surface structures are required will.

The highest demands on the metal surface in the production of metal-coated holograms posed, which is a common type of today Represent counterfeit protection. Holograms can be due the complex and costly manufacture, if imitated at all, only with relatively great effort and because of their optical properties, which depend on the viewing angle, good copy protection. Apart from the security aspects Holograms also like from an aesthetic point of view applied to documents of value.

Reflection holograms are usually either using specially prepared embossing matrices that match the Interference pattern of the hologram corresponding surface relief have produced by the surface relief embossed in a hardened lacquer layer and then metallized and with a protective lacquer layer is provided. Alternatively, the relief of the embossing die can be used also directly into a thin metal layer embossed and then with the protective lacquer layer be provided. The metallization ensures sufficient Brilliance of the hologram, making it visually good is recognizable.

Various options have already been proposed such metal layers or holograms in locally limited form on securities, banknotes or Apply ID cards. One of the most mature Techniques that are also preferred when applying holograms is used is preparing a separate one Hot stamping tape from which it is transferred to the end carrier is (DE-OS 33 08 831, US-PS 4,758,296). Here are placed on a substrate with an easily removable Separating layer is provided, those to be transferred Layers in reverse order as later on the document should be available. The top one Layer forms an adhesive layer, for example one Heat seal adhesive layer. Be over this adhesive layer the hot stamping tape and the document under the influence of Heat and pressure combined. The substrate of the Hot stamping tape can then due to the separation layer be pulled off effortlessly.

Although the transfer belt is made as a continuous belt will, d. H. the metallization in a continuous Process takes place (e.g. in a vacuum evaporation plant), only the desired areas transferred to the document. The transfer of to transferring surface areas can be different Species are accomplished. For example the adhesive layer is printed in a specific pattern be so that the layer structure to be transferred (if necessary with large-scale heating) only in places attached to the document or the one used in lamination Stamp has an outline shape that the conforming form, so that even when used of large-area heat seal adhesive only the areas of the adhesive layer are activated, to which the die applies pressure and heat (DE-OS 33 08 831).

However, this hot stamping transfer process is suitable only conditionally for the application of holograms on banknotes. Because banknotes are printed in steel gravure and that requires a rough paper surface the surface texture of the paper normally changes the thin transfer layer. The surface roughness of the paper overlays the relief structure of the hologram, of the diffraction grating or the like, whereby the hologram loses sharpness and brilliance. To this Avoid effect are on the banknote in the area of additional measures for the hologram to be applied Smoothing of the surface is necessary (EP-OS 0 440 045).

Such additional measures can be avoided by the banknote paper in this way with the lacquer layer to be embossed is provided that the applied in the liquid state Paint the bumps on the surface of the banknotes compensates.

For example, EP-OS 0 338 378 describes continuous process in which banknote paper in Roll form first printed on both sides and then in certain areas with a holographic structure is provided. Here, the varnish to be embossed and transfer the relief structure to the paper at the same time, by the surface structure of the die is covered with a radiation-curable lacquer. As soon as Paper and embossing stamp have been brought into contact, the paint is cured with UV radiation or electron beam. The paint now adheres to the paper surface and has the holographic relief structure. In the next Step this relief structure with the help of masks in metallized in a vacuum evaporation system. Around the thin Metal layer and the fine relief structure from abrasion and To protect destruction, the hologram area is in a further step with a protective layer.

A similar process is known from DE-OS 25 55 215 known. In this case, a thermoplastic Layer using a heated embossing die from one Transfer hot stamping foil to the document, at the same time the optical markings in the thermoplastic Layer are embossed. The carrier substrate is only peeled off after embossing and the relief structure then metallized.

This approach, i. H. emboss first and then metallizing has the major disadvantage that the metal layer the contours of the fine relief structure not exactly understand, but by different Deposits on vertical or horizontal structural elements blurred. This applies even in the cases in which the metal layer to be deposited is only a few nm thick is. The hologram therefore also loses brilliance.

The alternative approach, only after the Embossing metallization is also the state of the art Technology. For example, U.S. Patent 4,420,515 discloses a Process in which an already metallized paint surface is provided with a relief structure. An endless circulating transfer belt is continuously metallized and brought into contact with a document that selectively coats a varnish has been. The paint is hardened and binds the metal stronger than that Transfer ribbon and thus pulls the when separating transfer ribbon and document Metallization partially from this transfer belt. The final step is emboss the metallized lacquer area on the substrate.

As the embossed lacquer layer is embossed, the embossed relief shows a low contour sharpness. The quality of the hologram is also impaired this procedure. Furthermore, the embossing must be carried out with high pressure so that the embossing dies are subject to high wear are.

EP-OS 0 145 481 describes a method in which an embossing stamp vacuum-coated directly with a metal layer, the metallized stamp covered with liquid adhesive and pressed against a substrate, and the Adhesive layer is then cured.

The invention is therefore based on the object of a method and a device for the application of metal layers which may be locally limited To create substrates while avoiding the disadvantages mentioned above. Especially A method and a device for flexible hologram production is said to be based on difficult substrates and under difficult conditions will.

The solution to this problem can be found in the characterizing part of the main claim. Special embodiments and further developments are the subject of Subclaims.

The invention is based on the basic idea that the manufacture and the Transfer of a surface structure is only possible in optimal form, if the structures to be transferred are as pure as possible from the master structure are taken over and neither the transfer to the final substrate transferring structure still changed or damaged the structure of the master becomes.

According to the invention, the creation takes place in this sense not by embossing the structure to be transferred an existing flat metal layer, but through "Depositing" the metal layer on the master structure, the metal layer resembling a cast all Fills in structural elements of the master structure and detected. Master and metal layer thus have negative and Positive structures that complement each other completely and that are intimately connected. About changes or damage during transfer or at To avoid detachment of the metal layer from the master the two structures were only separated, after which the metal layer is fixed on the final substrate and mechanically stabilized by the substrate and adhesive layer is.

The term "structure" can be seen in general d. H. as a structure can be both extremely smooth reflecting surface as well as any relief structure Find use. It is important according to the invention that the selected or given structure if possible unadulterated as a positive or negative structure implemented and just as genuine on the substrate is transmitted.

The term "lacquer layer" is intended to cover all materials and Capture substances that in the transfer of the metal layer in To make it so soft and sticky that the metal layer with its back without damage is impressive in the layer, whereby the Metal layer on the one hand intimately connects with the lacquer layer and any bumps between the substrate surface and back metal surface and on the other hand the metal layer adheres so firmly that, if necessary after an additional curing phase, the Metal layer are completely removed from the master can.

• daß auf der Master-Struktur eine 1 : 1-Reproduktion durch Ablagern der Metallschicht erzeugt wird,
• daß entweder auf der Metallschicht oder dem Substrat eine Lackschicht aufgebracht wird, die zu dem Zeitpunkt, zu dem Substrat und Master in Berührung gebracht werden, ausreichend weich und klebrig ist und
• daß das Substrat zusammen mit der Metallschicht vom Master abgezogen wird, wobei die Lackschicht so weit dimensionsstabil ist, daß sie ein Abziehen der Metallschicht vom Master ermöglicht und die Metallschicht auch nach Trennung vom Master soweit stabilisiert, daß die vom Master übernommenen Strukturen erhalten bleiben.

In practice this means

• that a 1: 1 reproduction is created on the master structure by depositing the metal layer,
• that a lacquer layer is applied to either the metal layer or the substrate, which is sufficiently soft and sticky at the time when the substrate and master are brought into contact and
• that the substrate is removed from the master together with the metal layer, the lacquer layer being dimensionally stable to such an extent that it enables the metal layer to be removed from the master and the metal layer is stabilized even after separation from the master to such an extent that the structures adopted by the master are retained.

In this way it is ensured that the Metal layer present structure during the pressing process on the substrate so long from the master structure is stabilized until the paint layer has this supporting function can take over. The separation then takes place from the master and, if necessary, further processing to further stabilization, to protect against environmental influences, for further creative training etc. Such measures can be further hardening the lacquer layer, the application of a protective lacquer layer, the provision of blind embossing with different structures, overprinting with printing inks etc.

Since neither when creating the metal layer nor when Transfer of the same selective mechanical forces to the Master structure, are manufacturing and transfer process both for the master structure and for the in The structure of the metal layer is extremely gentle. Mechanical wear is during this manufacturing phase largely excluded.

As a carrier of the master structure z. B. a cylindrical Printing roller, an endless belt or a stamp etc. are used. The production of the metal layer takes place with the help of known metallization processes, such as Vacuum evaporation, electrolysis or photolysis as well other special processes that are used in technology under Special terms such as "Gas Jet Deposition (GJD)", "Spray Deposition", "Laser deposition" etc. are known. The Hardening the paint layer is different possible. This can happen when using a liquid hot melt adhesive for example, simply by cooling Multi-component paints by heating and depending on the use other substances also through other energy supply, e.g. B. by UV radiation, microwave radiation, Electron beam hardening etc.

The method according to the invention is particularly suitable for the transfer of locally limited metal layers, because both the metallization and the transfer process can be precisely defined and structured locally.

The production of the metallic surface elements takes place as already explained, on an intermediate carrier with the Master structure from which it is transferred to the substrate will. In contrast to known methods in which the metallization directly on the substrate itself this procedure offers the advantage that any metallization process can be used can, d. H. also methods can be used, which at direct application to the substrate will destroy it or damage the substrate.

Photolytic ones are particularly advantageous for metallization Process, e.g. B. as in DE-OS 38 40 199 or DE-OS 38 40 200 described, which offer the possibility the metallic surface elements in their outline shapes particularly easy to modify, so that on this Way, in a particularly economical form series of different Surface elements or surface elements can be produced with varied additional information content are.

• Konditionierung des Zwischenträgers, d. h. Ergreifen von auf das Metallisierungsverfahren abgestimmten Maßnahmen zur Auswahl der zu metallisierenden Bereiche des Zwischenträgers,
• Metallisierung des Zwischenträgers,
• Transfer der lokalen Metallschichten auf das Substrat,
• Reinigen des Zwischenträgers.

The metallization process basically consists of the following steps:

• Conditioning the intermediate carrier, ie taking measures tailored to the metallization process for selecting the regions of the intermediate carrier to be metallized,
• Metallization of the intermediate carrier,
• Transfer of the local metal layers to the substrate,
• Clean the intermediate carrier.

• die flächige Sensibilisierung des Masters mit einem Katalysator bzw. Precursor, z. B. Palladiumacetat,
• die optische Aktivierung des Palladiumacetats mit UV-Strahlung sowie
• die Metallabscheidung in den sensibilisierten und aktivierten Flächenbereichen.

In the photolytic process, the conditioning of the intermediate carrier (master) can be divided into individual steps, namely

• surface sensitization of the master with a catalyst or precursor, e.g. B. palladium acetate,
• the optical activation of the palladium acetate with UV radiation and
• metal deposition in the sensitized and activated areas.

By deliberately influencing one or more of the three Partial steps can be a varied variation of the continuous created metallizations. This is possible, for example, by sensitizing the Masters takes place in localized form. All subsequent ones Work steps can then be carried out over a large area because a metal deposit only on the Places where the catalyst is present. Alternatively, after extensive sensitization the activation can be carried out selectively. This Variant is therefore particularly advantageous because of this Way, for example, with the help of a controlled UVLasers can also display very fine and sharply defined lines are. These structures remain subsequent full-surface wetting in wet chemical Baths for electroless metallization in their fine Get "line". Ultimately, that too local limitation of the metal layers by defined Apply the wet chemical agent to a large area sensitized and activated master surface will.

If the shape of the metal layers over several cycles remains the same, you can, if necessary, click again Conditioning of the intermediate carrier can be dispensed with, d. H. the intermediate carrier is not complete in the last step cleaned, but only from metal residues exempted.

In the special case of hologram or diffraction structure application is the embossing roller according to the invention metallic coated. This results in another one inventive aspect. Because with the invention The process makes it possible for the first time to produce holograms or embossing, metallization of the embossed hologram and Transfer of the metallized hologram in a continuous Workflow.

This is particularly advantageous where it used to be when subsequently placing the metallization Registration problems had to be solved, especially in the cases in which a pressure cylinder as an intermediate carrier for master and metal layer, all from printing technology known process steps and tolerance ranges are usable. With the method according to the invention one has in addition, for the first time, the possibility of current data at the Include variation of the surface elements. This for example, when used for securities, ID cards, identification cards etc. make sense, because this also includes serial number, personal alphanumeric or pictorial (photo!) data in the Creation of the metal layer to be included can.

In addition to these design options and advantages you also get an absolutely faithful reproduction the master structure because the metal layer is the master structure fully molded. This looks like already mentioned, advantageous in optical quality of the hologram diffraction structures etc. noticeable.

Further advantages and special embodiments of the Invention emerge from the following examples, which be explained with reference to figures.

Fig. 1

das erfindungsgemäße Grundprinzip,

Fig. 2

elektrolytische Metallisierung einer zylindrischen Druckwalze bzw. Prägeform und Transfer der Metallisierung auf ein ein Substrat,

Fig. 3

Schichtaufbau des Substrats nach dem Metalltransfer,

Fig. 4

photolytische Metallisierung einer zylindrischen Druckwalze bzw. Prägeform,

Fig. 5

photolytische Metallisierung einer zylindrischen Hochdruckwalze und Transfer der Metallisierung auf ein Substrat,

Fig. 6

elektrolytische Metallisierung eines endlosen Druck- nzw. Prägebandes und Transfer der Metallisierung auf ein Substrat,

Fig. 7

photolytische Metallisierung eines endlosen Druck- bzw. Prägebandes,

Fi.g 8

metallische Vakuumbedampfung eines endlosen Druck- bzw. Prägebandes,

Fig. 9

Schichtaufbau eines photolytisch metallisierten Prägebandes.

Show it:

Fig. 1

the basic principle according to the invention,

Fig. 2

electrolytic metallization of a cylindrical pressure roller or embossing mold and transfer of the metallization to a substrate,

Fig. 3

Layer structure of the substrate after the metal transfer,

Fig. 4

photolytic metallization of a cylindrical pressure roller or embossing mold,

Fig. 5

photolytic metallization of a cylindrical high-pressure roller and transfer of the metallization to a substrate,

Fig. 6

electrolytic metallization of an endless pressure or Embossing tape and transfer of the metallization to a substrate,

Fig. 7

photolytic metallization of an endless printing or embossing tape,

Fi.g 8

metallic vacuum evaporation of an endless printing or embossing tape,

Fig. 9

Layer structure of a photolytically metallized embossing tape.

Fig. 1 shows in schematic form the basic principle of Invention. According to this scheme, in a first Master 1 station with a metal layer. As already explained in the introduction, the master 1 has one any kind of surface structure 3, in the illustrated Case a surface relief, on this relief 3 a metal layer 2 is applied such that the Structure 3 in the metal layer 2 as an exact negative structure is present. The metal layer 2 is preferred locally limited or has a defined outline contour on.

A substrate 4 is prepared in a second work station, that can be almost any medium. in the The present case is a security with glued, natural rough surface.

A paint coater is another work station provided with either on the metal layer 2 or a locally limited one on the substrate 4 Lacquer layer can be applied. The local limit the lacquer layer preferably corresponds to that of Metal layer 2. However, it is also conceivable that both contours deviate from one another, taking note is that the metal layer only in the areas of Master is defined in which they are subtracted with the Paint layer is in cover.

After the paint coating, Master 1, metal layer 2, lacquer layer 6 and substrate 3 merged and together pressed. The arrows 7, 8 should be the Symbolize pressure.

Depending on which varnish is used, it may be by additional measures the lacquer layer 6 harden at least to the extent that sufficient Adhesion to metal layer 2 and substrate 4 and a Intrinsic strength is ensured, which is a deduction from Master while stabilizing the metal layer 2 enables. In the simplest case, curing can take place by the lacquer layer 6 a heated Hot melt adhesive is made by cooling Master 1 and Metal layer 2 relatively quickly after merging stiffens. Substances can also be used in the same way under the influence of IR or UV rays, Harden microwaves, electron beams etc. In the event that the lacquer layer has a consistency, the pressing in without additional measures and gluing the layers as well as peeling off and stabilizing the metal layer allows that final curing, if desired, also to one happen at any later time.

In the last station shown in Fig. 1 that is Substrate 4 together with metal layer 2 from master 1, e.g. B. in the direction of arrow 9. The on this Metal layer transferred to the substrate is different after subsequent use, there may be further work steps, such as B. the equipment with a transparent Protective lacquer layer to submit. These others However, steps are familiar to the person skilled in the art and do not need to be explained here.

In the exemplary embodiments described below are different applications of the invention Principle explained.

For reasons of clarity, in FIG. 1 and the other figures on a scale and detail Not shown. Rather, the figures show basic arrangements that carry out allow the inventive method. In the figures functionally identical elements with the same reference numbers Mistake.

example 1

In Fig. 2, a cylindrical pressure roller with a smoother Partially metalized surface electrolytically and with an adhesive coated substrate in Brought in contact.

The web-shaped substrate 4, in the present case paper, is conveyed by a transport system shown in Fig. 2 is indicated by the rollers 10. Before the web material 4 of the printing roller 11 is fed, passes through there is a paint coating station 5. The web 4 is here with the help of an engraving or stencil cylinder 12 in certain areas with a transparent adhesive coated.

Then the substrate 4 passes through the transfer zone, that of the cylindrical transfer roller 11 and one cylindrical counter-pressure roller 13 is also formed. In the contact zone of coated substrate 4 and Metallized transfer roller 11 can additionally harden the adhesive, e.g. B. by polymerization with Electron beams or UV radiation take place. At the The metal coating is conveyed further 2 deducted from the intermediate carrier 11. In a further processing station 14 can the metallized Area 2 but also, if necessary, the entire or larger areas of the material web 4 with be provided with a transparent protective lacquer layer. The one provided with metallic surface elements 2 Material web 4 can finally further printing stations 15 are supplied to them with alphanumeric characters or to print patterns, which may also be parts the metal coating 2 can cover. It is the same conceivable, instead of conventional printing inks, special printing inks mixed with feature substances use that in the visual spectral range transparent could be. Suitable substances are, for example Fluorescent substances, magnetic or pearlescent pigments.

3 shows the layer structure of the metallized substrate 4 after passing through the protective lacquer coating station 14. Directly on the substrate 4 is the in Station 5 arranged locally applied adhesive layer 6. Because this layer 6 is transparent and very thin and therefore the visual impression of the end product not impaired, their areal expansion does not have to correspond exactly to the dimensions of the metallization 2.

In any case, the expansion of the adhesive layer 6 not be smaller than the intended metallization 2, because this results in incomplete metal transfer would have. To the metallization 2 from abrasion and destruction to protect it is also made of a transparent Protective lacquer layer 16 covered.

In the metallization station shown in Fig. 2 , as already mentioned, the intermediate carrier, here the cylindrical roller 11, with those to be transferred metallic surface elements 2 provided.

In this example, the transfer roller 11 is on electrolytic Metallized away. The parts of the cylinder, that should not be metallized are used in the Station 19 coated with electrically insulating material, e.g. B. with a layer of paint. In the direction of rotation the pressure roller 11 seen next station the roller 11 passes through a galvanic bath 17. The in metal loosened in the bathroom is Transfer cylinder 11 and the voltage applied to the bath the electrically conductive surface areas of the roller 11 so that a metallic pattern on the roller surface arises. In the following washing station 18 chemical residues are removed. The metal coating 2 is now transferred to the substrate 4. Subsequently the roller 11 in the station 20 of eventual Remains of metal cleaned. If the outline (or shape) the metal coating are to be changed, so in the cleaning station 20 the electrically insulating Coating of the roller 11 also removed. In the Paint coating station 19 finally becomes roller 11 prepared for the next metallization cycle.

Example 2

Fig. 4 shows a metallization station in which the cylindrical transfer roller on photolytic Paths partially metallized and coated with an adhesive Substrate is brought into contact. The Vorund Aftertreatment of the substrate 4 and the transfer of metallic areas is analogous to the example 1. For this reason, an illustration has been given in FIG the corresponding additional processing stations waived.

Photolysis is a modern metallization process that has been successful for several years in the metallic coating of semiconductor components (DE-OS 38 40 199) or in the manufacture of metal fleece to shield electrical fields (DE-OS 38 40 200) was used.

At the beginning of the metallization cycle, the intermediate carrier 11 wetted with a palladium acetate film. To is powdered palladium acetate in a solvent, such as B. chloroform, dissolved and by immersion, Spray or spin applied. 4 shows representative of a diving station 21. The solvent evaporates immediately and leaves a thin film of palladium acetate, whose thickness over the concentration of Solution and the application process can be set can. In station 22, the ones to be metallized Areas of the printing roller exposed to UV radiation by selective photo splitting at the exposed areas to make a thin layer of palladium. This only a few nm thick palladium layer then serves as Activator for the subsequent chemical metallization, at which micrometer thick copper, nickel and gold layers can be applied. 4 is a Metallization bath 23 shown, in which the intermediate carrier roller 11 dips. In another variant can the metallization also by means of a suitable Printing process, e.g. B. in screen printing, on the intermediate carrier 11 can be printed directly.

The unexposed are exposed in the cleaning station 24 and thus non-metallized palladium acetate residues as well Liquid residues from the metallization bath 23, which are left on the roller 11, rinsed.

Since the metal 2 is exactly congruent with the activated or exposed areas of the palladium acetate film is the decisive factor Advantage that with sharply contoured and high resolution Exposure, e.g. B. by a computer-controlled UV laser beam (e.g. eximer laser), any, too different, finely structured per exposure process Surfaces can be metallized.

After the transfer of the metallization 2 to the substrate 4 the intermediate carrier 11 is cleaned in station 25. After that the procedure described above is repeated cyclically.

The finished substrate has the in this example same layer structure as in Example 1, based on 3.

Example 3

Instead of a printing roller with a smooth surface, for example also a cylindrical high-pressure roller (letterpress) can be used as shown in Fig. 5. in the shown example, this roller is also after metallized photolytic process. Here too runs the pretreatment and aftertreatment of the substrate 4 analogously to Example 1.

The process steps for metallizing the high pressure roller 26 are analogous to example 2. The sublime Areas 27 of the pressure roller 26 are made with palladium acetate 21 wetted and according to the transfer Information irradiated over a large area with UV light 22. This in metal dissolved in the plating bath 23 opens up the activated areas while the unexposed areas Areas cleaned in the cleaning station 24 will.

In the contact zone between substrate 4 and the raised ones Printing areas 27 is previously on the substrate applied adhesive hardened and thus binds the Metal layer 2 to the substrate 4. Before the metallization cycle starts again, the print areas 27 completely cleaned in station 25.

Example 4

In this example, which is shown in Fig. 6, serves an endless belt 28 with a smooth surface as an intermediate carrier, which is partially electrolytic metallized and with the adhesive-coated substrate 4 is brought into contact.

However, the substrate is here only with a Component 29 of the metal coating 2 from the intermediate carrier 28 peeling lacquers locally coated. Subsequently the substrate 4 becomes analogous to the previous ones Examples transported through the transfer zone and possibly aftertreated in accordance with Example 1.

In this case, the metallization station consists of an endless belt 28 running over the rollers 30, 31, that is electrolytically metallized. According to example 1 the endless belt 28 is prepared in the stations 20 and 19 and then locally in the galvanic bath 17 metallized. After cleaning up troublesome bathroom residues in station 18, metallization 2 becomes the second Component 32 of the releasing lacquer, e.g. B. an adhesion promoter for the metal layer to be transferred and / or a hardener for the first component. In the Touching the two components in the transfer zone causes the diffusion of the hardener together with energy supply, to match the substances used in each case is an accelerated curing and a very good binding of the transferred metal layer to the substrate.

This two-component adhesive can of course also be used all other examples described are used.

Example 5

Another variant of a metallization station is in Fig. 7 shown. The pretreatment or post-treatment of the substrate 4 take place analogously to example 1. FIG. 7 shows therefore only for the metallization of the endless belt 28 necessary devices and the the transfer zone forming rollers 13 and 30.

The partial metallization of the intermediate carrier 28 happens here analogously to Example 2 after the photolytic Method. The endless belt 28 is with the Palladium acetate film 21 wetted by UV radiation 22 in places for the metal deposition in the metallization bath 23 is activated. Stations 24 and 25 ensure that the belt is cleaned as already described 28

Example 6

In this example, too, the pre-treatment or post-treatment of the substrate runs according to the preceding examples, the representation in FIG. 8 is also limited to the metallization station and the transfer zone. The endless belt 28 serving as an intermediate carrier becomes partially through a vacuum coating over masks metallized.

The tape 28 is in before each metallization cycle Station 33 cleaned of any metal residues. Conditioning the areas to be coated are in the vacuum chamber 34 itself, if necessary, with the help of masks 35. As a vacuum coating process can do both vacuum evaporation and cathode ray sputtering (Sputtering) used will. The transfer of the metallic areas proceeds as already explained, by curing or cooling the Adhesive in the contact zone of substrate 4 and endless belt 28 between the rollers 13 and 30.

The shown in Figs. 2 to 8 and in the examples 1-6 described methods for local Metallization of a substrate can also be very beneficial for the reflective coating of a diffraction structure, preferably a hologram will. In this case, the intermediate carrier is used as an embossing mold trained, d. H. he carries on his surface the diffractive relief structure, which according to the state of the Technology is embossed into the paint on the substrate. Optionally, as already stated, the paint can also be applied the metallized areas of the intermediate carrier applied and simultaneously with the metal layer on the Substrate are transferred.

The inventive metallization of the insensitive Embossing instead of the sensitive substrate allows it chemical metallization with aggressive chemicals perform. The following examples show metallization stations described as such Have embossed intermediate carrier.

All made in connection with the above examples Statements regarding procedural variants can easily be transferred to the following examples.

Example 7

A cylindrical pressure roller with a relief-like surface structure becomes partial or full electrolytic metallized and coated with an adhesive Contacted substrate.

The device shown in Fig. 2 can in principle be taken over. Only the cylindrical pressure roller 11 must have a relief surface corresponding to the hologram exhibit.

The substrate 4, e.g. B. a paper web is preferred with an engraving or template cylinder 12 placed, locally coated with a varnish 5 on the places where the hologram should be embossed. Subsequently, the substrate 4 in the embossing and Metal transfer zone between the pressure roller 13 and the metallized die 36 transported. The cylindrical Embossing mold 36 has the hologram embossing structure placed in register with respect to the locally coated Surfaces of the substrate 4.

The surface relief of the embossing die 36 is after the Electrolytic processes already described in Example 1 fully or partially metallized. The Metallization can also be carried out over the entire area because the register-accurate transfer by the coated Places on the substrate 4 is determined. A sharper one Contouring of the metal surfaces 2 is however by partial Metallization of the embossing mold 36 is achieved.

In the contact zone of coated substrate 4 and The relief structure becomes detachable and metallized transferred true to the original into the paint. At the same time the paint is cured e.g. B. by cooling, UV radiation or polymerization with electron beams. As in Example 1, the hardened lacquer layer is drawn the metallization from the die 36.

In this way, work steps in hologram production can be saved because embossing and mirroring the relief structure at the same time in one Work step.

The remaining process steps are the same as for example 1.

Example 8

In the metallization device described in Example 2 and FIG. 4 becomes the cylindrical pressure roller with a smooth surface 11 by a likewise cylindrical Embossing die 36 replaced and photolytically metallized.

Examples 9-11

The metallization devices described in Examples 4-6, which is an endless belt as an intermediate carrier can be used in the combined hologram embossing or metallization used according to the invention will. The endless belt 28 carries in these cases the hologram relief structure.

Fig. 9 shows a section of the on photolytic Path metallized embossing tape 37 (Fig. 7) before using it is brought into contact with the substrate 4. The endless belt 37 has a relief structure 38. Above the relief structure 38 there is a thin palladium layer 39, by photolytically decomposing the palladium acetate film arose. The unexposed areas of this Films were removed in station 24. Over the palladium layer 39 the metal 2 has deposited. It has exactly the outline shapes of the palladium layer 39 and reproduces the relief structure 38 true to the original.

By simultaneously transferring metallization and Relief structure, quality losses are avoided arise from the subsequent application of the mirroring, because the subsequently evaporated metal layer the relief structures are blurred. At the same time the negative influence of the surface structure of the substrate avoided because the varnish layer roughened the surface compensates.

The measures known from EP-OS 0 440 045 for Smoothing the surface in the area of the later to be applied Holograms can of course still be made if this is due to special circumstances, e.g. B. because, for certain reasons, particularly thin layers of lacquer to be used should be necessary.

The photolytic metallization of the embossing mold offers how already explained the possibility of finely structured to produce metallic surfaces. This fact is too especially when designing holograms in combination with other features of great advantage. So it can Hologram, for example with a line or guilloche frame be provided or rasterized so that a background print remains visible. It would also be conceivable Cutouts in the form of characters or patterns to be provided in the metallization. Because of the variable Exposure options of the palladium acetate film could also a sequential numbering in the form of metallic Numerals can be provided on the hologram.

Contrary to the usual requirement in technology Metal coatings, the best possible adhesion of the To achieve coating is a detachable according to the invention Adhesion of the metal layer on the master surface required.

• Die "Master"-Oberflachenstruktur darf keine "Unterschneidungen", "Hohlungen" oder "Überhänge" aufweisen, sondern nur einfache "Berge" und "Täler". Dies ist bei glatten Oberflächen oder bei Hologrammreliefs gegeben.
• Die "Master"-Substanz und die Metallisierungssubstanz dürfen chemisch nicht zu eng verwandt sein, z. B. ist Kupfer auf Messing ungeeignet, Kupfer auf Aluminium oder auf vielen Kunststoffen geeignet für die Herstellung einer lösbaren Verbindung.
• Durch Anpassung der Schichtstärke und des Aktivierungsgrades des Precursors bei der photolytischen Metallisierung läßt sich die Lösbarkeit der Metallschicht einstellen.
• Durch die Stromstärke und damit durch die Schnelligkeit der Ablagerung läßt sich bei der elektrolytischen Beschichtung die Haftung der Schicht einstellen. Eine schnelle Ablagerung ergibt eine lösbare Schicht.
• Bei Aufdampfen einer Metallisierung erhält man durch vorheriges Aufbringen einer monomolekularen Schicht eines Trennmittels eine lösbare Schicht, falls man nicht vorzieht, die Masterform direkt aus einer Substanz herzustellen, die eine schlechte Haftung für die Metallbedampfung bietet.

This is less of a problem than producing a good one. While only a few materials have to adhere well to one another and in general additional measures (such as roughening the surface) have to be applied, poor adhesion with coatings is normal and easy to achieve if the following is observed.

• The "master" surface structure must not have "undercuts", "hollows" or "overhangs", but only simple "mountains" and "valleys". This is the case with smooth surfaces or with hologram reliefs.
• The "master" substance and the metallization substance must not be chemically closely related, e.g. B. copper on brass is unsuitable, copper on aluminum or on many plastics is suitable for the production of a detachable connection.
• The solubility of the metal layer can be adjusted by adjusting the layer thickness and the degree of activation of the precursor in the photolytic metallization.
• Due to the current intensity and thus the speed of the deposition, the adhesion of the layer can be adjusted in the electrolytic coating. A quick deposit results in a detachable layer.
• In the case of metallization vapor deposition, a monolayer of a release agent is applied beforehand to produce a releasable layer, if one does not prefer to produce the master mold directly from a substance which offers poor adhesion for metal vapor deposition.

• des Zwischenträgers (zylindrische Druckwalze, Endlosband, Stempel),
• der Struktur (hochglanzend, Grobstruktur, Mikrostruktur, Hologramm, Beugungsgitter etc.),
• des Metallisierungsverfahrens,
• der Art der lokalen Begrenzung (begrenzte Metallschicht auf dem Master oder begrenzte Kleberschicht),
• der Plazierung des Klebers (auf Metallschicht oder Substrat),
• des Klebers und des zugehörigen Aushärteverfahrens,
• der zusätzlichen Schritte zur Stabilisierung etc.

The introductory remarks show that the range of variations is far from exhausted by the examples mentioned. In principle, there are some function blocks in the method according to the invention, in which, in turn, very different design variants can be used. A variation is particularly useful in the selection

• the intermediate carrier (cylindrical pressure roller, endless belt, stamp),
• the structure (high-gloss, rough structure, microstructure, hologram, diffraction grating etc.),
• the metallization process,
• the type of local boundary (limited metal layer on the master or limited adhesive layer),
• the placement of the adhesive (on metal layer or substrate),
• the adhesive and the associated curing process,
• the additional steps for stabilization etc.

Another basic variant is based on the Waive substrate. In this example the paint cured directly on the metallic intermediate carrier and with the metal layer as a self-supporting film deducted.

Although only a few of the possible combinations have been described no final selection can be made. Further Combinations under the general inventive concept should also fall under the Scope of protection fall.

Claims (23)

1. A method for producing a metal layer (2) having a defined surface structure (3, 38) on a substrate (4), the metal layer (2) being prepared on an intermediate carrier (11, 26, 28, 36, 37) in detachable form and then transferred to the substrate (4), characterized by the following steps:

   a) equipping the intermediate carrier (11, 26, 28, 36, 37) with a master structure (3, 38), the intermediate carrier (11, 26, 28, 36, 37) being a continuously circulating medium,

   b) applying the metal layer (2) to the master structure (3, 38) of the intermediate carrier (11, 26, 28, 36, 37),

   c) coating the substrate (4) or metal layer (2) with a layer of lacquer (6),

   d) bringing together the metal layer (2), layer of lacquer (6) and substrate (4) in a stage when the layer of lacquer (6) is present in a sufficiently soft and sticky form,

   e) hardening the layer of lacquer (6),

   f) separating the intermediate carrier (11, 26, 28, 36, 37) and substrate (4) while simultaneously removing the metal layer (2) in contact with the layer of layer (6) from the intermediate carrier (11, 26, 28, 36, 37).
2. A method for producing a metal layer having a defined surface structure on a substrate, the metal layer being prepared on an intermediate carrier in detachable form and then transferred to the substrate, characterized by the following steps:

   a) equipping the intermediate carrier with a master structure,

   b) applying the metal layer to the master structure of the intermediate carrier,

   c) coating the metal layer with a layer of lacquer,

   d) hardening the layer of lacquer,

   e) separating the intermediate carrier and substrate while simultaneously removing the metal layer in contact with the layer of layer from the intermediate carrier, the hardened layer of lacquer constituting the substrate as a self-supporting film.
3. The method of claim 1, characterized in that the substrate (4) is smoothed before step c) in the area to be coated.
4. The method of claim 1 or 2, characterized in that the intermediate carrier (11, 26, 38) is equipped with an extremely smooth surface.
5. The method of claim 1 or 2, characterized in that the intermediate carrier (36, 37) is equipped with a surface relief (39) in the form of a diffraction structure, in particular a hologram.
6. The method of at least one of claims 1 to 5, characterized in that the metal layer (2) is produced by photolysis, electrolysis, gas jet deposition, spray deposition or laser deposition.
7. The method of at least one of claims 1 to 6, characterized in that the layer of lacquer (6) is hardened by a change of temperature or by UV, microwave or electron radiation.
8. The method of at least one of claims 1 to 7, characterized in that the substrate (4) is subjected to aftertreatment after the metal layer (2) is applied.
9. The method of claim 8, characterized in that the substrate (4) is provided with a protective lacquer in the area of the metal layer (2).
10. The method of claim 8 or 9, characterized in that the substrate (4) is printed or provided with a blind stamp, possibly also in the area of the metal layer (2).
11. The method of at least one of claims 1 to 10, characterized in that the master structure (3, 38) is produced on a cylindrical press roll, a letterpress cylinder or an endless band.
12. The method of at least one of claims 1 to 11, characterized in that the metal layer (2) is produced on the intermediate carrier (11, 26, 28, 36, 37) in locally limited form.
13. An apparatus for producing a metal layer provided with a defined surface structure on a substrate, the metal layer being prepared on an intermediate carrier and then transferred to the substrate, characterized in that the apparatus has the following means:

    a) a continuously circulating intermediate carrier provided with a master structure and having the metal layer produced thereon in detachable form,

    b) an apparatus consisting of at least one unit for applying the metal layer to the intermediate carrier provided with the master structure,

    c) a unit for coating the intermediate carrier with lacquer,

    d) an apparatus for hardening the layer of lacquer,

    e) an apparatus for separating the hardened layer of lacquer and the intermediate carrier, the metal layer which is contact with the layer of lacquer being removed from the intermediate carrier, and the hardened layer of lacquer forming the substrate as a self-supporting film.
14. An apparatus for producing a metal layer (2) provided with a defined surface structure (3, 38) on a substrate (4), the metal layer (2) being prepared on an intermediate carrier (11, 26, 28, 36, 37) and then transferred to the substrate (4), characterized in that it has the following means:

    a) a continuously circulating intermediate carrier (11, 26, 28, 36, 37) provided with a master structure (3, 38), the metal layer (2) being produced on said carrier in detachable form,

    b) an apparatus (17, 18, 19, 20, 21, 22, 23, 24, 25) consisting of at least one unit for applying the metal layer (2) to the intermediate carrier (11, 26, 28, 36, 37) provided with the master structure (3, 38)

    c) a unit (5, 12) for coating the substrate and/or metal layer with lacquer,

    d) a unit (11, 13, 30, 31) for temporarily bringing together the intermediate carrier (11, 26, 28, 36, 37) and substrate (4),

    e) an apparatus for completely hardening the layer of lacquer (6) at the place where the metal layer (2) is brought in intimate contact with the substrate (4) on the carrier via the still soft, sticky layer of lacquer (6).
15. The apparatus of claim 13 or 14, characterized in that the intermediate carrier (36, 37) has a surface relief in the form of a diffraction structure, in particular a hologram.
16. The apparatus of claim 13 or 14, characterized in that the intermediate carrier (11, 26, 28) has an extremely smooth surface.
17. The apparatus of at least one of claims 13 to 16, characterized in that the intermediate carrier is a cylindrical press roll (11, 36), an endless band (28) or a letter-press cylinder (26).
18. The apparatus of at least one of claims 13 to 17, characterized in that apparatus b) for applying the metal layer (2) to the intermediate carrier (11, 26, 28, 36, 37) has the following means:

    f) a coating unit (19) for providing the areas of the intermediate carrier (11, 26, 28, 36, 37) not to be coated with electrically insulating material,

    g) an electrolytic bath (17) for coating the electrically conductive areas of the intermediate carrier (11, 26, 28, 36, 37) with metal.
19. The apparatus of claim 18, characterized in that cleaning means (18, 20) are provided before unit f) and possibly after unit g).
20. The apparatus of at least one of claims 13 to 17, characterized in that apparatus b) for applying the metal layer (2) to the intermediate carrier (11, 26, 28, 36, 37) has the following means:

    f) a wetting unit (21) for wetting the intermediate carrier (11, 26, 28, 36, 37) with a palladium acetate film,

    g) a UV exposure unit (22) for activating the palladium acetate, possibly locally,

    h) a metalizing unit (23) for metalizing the exposed palladium acetate areas.
21. The apparatus of claim 20, characterized in that a cleaning apparatus (24, 25) is provided before unit f) and possibly after unit h).
22. Use of the apparatus of at least one of claims 13 to 21 for producing a data carrier, preferably of antifalsification paper.
23. Use of the method of at least one of claims 1 to 12 for producing a data carrier, preferably of antifalsification paper.

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